51. A pelton turbine develops a power of 2500 kW at 200 rpm under a net head of 400m. Calculate its approximate specific speed.
- 9
- 3
- 8
- 6
52. The unit power Pu of a turbine developing power P under head H is equal to
- P/H2.5
- P/H0.5
- PH1.5
- P/H1.5
53. In all reaction turbines, for maximum efficiency,
- the velocity of swirl at the entrance must be zero
- the velocity of flow at outlet must be zero
- the velocity of swirl at the outlet must be zero
- the velocity of flow at entrance must be zero
- temperature of fluid must remain constant
54. A turbine develops 500 kW power under a head of 100 m at 200 rpm. What would be its normal speed under a head of 81 m?
- 250 rpm
- 670 rpm
- 550 rpm
- 900 rpm
- 180 rpm
55. ___________ is a tangential-flow impulse turbine.
- Pelton wheel turbine
- Kaplan turbine
- Francis turbine
- Propeller turbine
- Draft tube
56. In a Francis turbine, the water
- flows out through a closed draft tube
- flows out openly
- either flows out through a draft tube or openly depending on the type of design
- neither flows out openly nor through a closed draft tube
57. Name the ratio of power available at the shaft of a turbine to the power delivered by water to the runner.
- volumetric efficiency
- overall efficiency
- mechanical efficiency
- hydraulic efficiency
58. Governing of a turbine means
- the head is kept constant under all conditions of working
- the speed is kept constant under all conditions of working
- the discharge is. kept constant under all conditions of working
- the frictional loss is kept constant under all conditions of working
59. Which of the following statement(s) is/are incorrect?
- A turbine is called impulse turbine if at the inlet of the turbine total energy is only kinetic energy
- A turbine is called reaction turbine if at the inlet of the turbine the total energy is kinetic energy and pressure energy
- The inward flow reaction turbine having radial discharge at outlet is known as Kaplan turbine
- Only iii
- Only i
- ii and iii
- i and ii
60. To generate 8100 kW under a head of 81 m while working at a speed of 540 r.p.m., what type of turbine is suitable?
- Pelton
- Francis
- Bulb
- Kaplan